Alkyl-substituted disiloxanes

ABSTRACT

NOVEL DISILOXANES OF THE FORMULA RR&#39;&#39;(CH3)SIOSI(CH3)R&#39;&#39;R IN WHICH R IS AN ALKYL RADICAL OF FROM 14 TO 30 CARBON ATOMS AND R&#39;&#39; IS A METHYL OR PHENYL RADICAL, HAVE UTILITY AS LUBRICANTS AND RELEASE AGENTS.

United States Patent ()1 hoe 3,632,619 Patented Jan. 4, 1972 US. Cl. 260448.2 R 4 Claims ABSTRACT OF THE DISCLOSURE Novel disiloxanes of the formula RR'(CH )SiOSi(CH )RR in which R is an alkyl radical of from 14 to 30 carbon atoms and R is a methyl or phenyl radical, have utility as lubricants and release agents.

The present invention relates to novel disiloxanes. More particularly, these disiloxanes are of the formula in which each R is independently selected from the group consisting of alkyl radicals having from 14 to 30 inclusive carbon atoms and each R is independently selected from the group consisting of methyl and phenyl radicals.

Silicone chemistry has reached a stage of detailed development. Most of the technology is focused on the monomeric silanes and on higher polymeric siloxanes, such as used for lubricants or elastomers. Relatively little effort has been expended in the area of disiloxanes, the polysiloxanes containing the least number of silicon atoms.

By the practice of the present invention, there is provided a class of novel disiloxanes which have utility as lubricants and release agents.

The higher alkyl substituted disiloxane of the invention includes and mixtures thereof.

The novel disiloxanes of the invention can be prepared by reacting H(R)CH SiOSiCH (R)H with unsaturated hydrocarbons of the formula CH=CH (CH CH or with mixtures of such hydrocarbons in the presence of a platinum catalyst such as chloroplatinic acid. An alternate method involves the preparation of RR (CH SiCl by the reaction of HR'(CH )SiCl with the described unsaturated hydrocarbon in the presence of chloroplatinic acid and subsequent hydrolysis of the product chlorosilane to obtain the disiloxane. Conventional hydrolysis techniques are utilized.

The disiloxanes containing the shorter chain alkyl substituents (C C are low viscosity fluids at room temperatures, while the higher alkyl substituted compounds are solid waxy materials. As compared to longer chain polymeric siloxanes, the disiloxanes of the invention exhibit much greater resistance to gelling at elevated temperatures. This high temperature stability is a particular advantage in applications, such as die casting, where buildup of the lubricant or release agent is undesirable.

In addition to being lubricants in the normal sense of the word, as used on moving metal surfaces, the novel disiloxanes function as internal lubricants when used as additives for thermal plastic materials, such as nylon, providing greater ease of extrusion of such materials. The (Cgf-Czg)(CH3)2SiOSi(CH3)2(C22-C2g) species is especially preferred in that it not only provides internal lubrication but significantly improves the impact strength of polyamide extrusions at the one weight percent additive level.

The following examples are illustrative, and are not intended to limit the invention which is properly delineated in the claims.

EXAMPLE 1 A 3-liter flask fitted with a mechanical stirrer, thermometer, addition funnel and condenser was charged with 1357 grams (6.92 mols) of l-tetradecene. To this, was added 0.2 milliliter of a chloroplatinic acid solution (0.1 molar chloroplatinic acid in isopropanol). The solution was stirred and heated to C. and 421.8 grams (3.18 mols) of H(CH SiOSi(CH H was added slowly from the addition funnel at a rate suflicient to keep the reaction temperature at C. The reaction was exothermic. When all the disiloxane had been added, the solution temperature was maintained at 120 overnight while stirring to complete the reaction.

The reaction product was stripped at a temperature of 204 C./0.4 mm. Hg of hydrogen to remove the unreacted olefin. The product was cooled, treated with activated carbon and filtered to obtain 1419 grams of C H (CH SiOSi(CH C I-I disiloxane Was a clear water-white fluid having a viscosity of 20.2 cs. at 77 F., a flash point of 475 F. and a freezing point of 18 C.

EXAMPLE 2 A five-liter flask, fitted with mechanical stirrer, thermometer, reflux condenser and addition funnel was charged with 1855 grams (6.5 mols) of a normal alpha olefin fraction containing species having from 22-28 inclusive carbon atoms and 0.5 milliliter of 0.1 molar chloroplatinic acid in isopropanol. This mixture was heated to C. while stirring moderately and 360 grams of H(CH SiOSi(CH H was added at such a rate that the exotherm from the reaction was maintained at a temperature from 125 to 150 C.

After the addition was complete, the reaction mixture was heated at C. overnight to complete the reaction.

The reaction product was stripped at 260 under vacuum to remove the unreacted olefin. It was then cooled, treated with activated carbon and filtered to obtain a mixture product of the formula 22 45 2s 57) 3 zsiosi 3 2( z2 45 2a 57) which was a white waxy material having a melting point of 35-45 C.

Disiloxanes of the formula 1a s7( a)2 3)2 1a a'1 and (C16H33"'C20H41) 3 asiosi 3 2 1s a3 20 41) were produced by reacting the corresponding alpha-olefin with the disiloxane utilizing the above described method.

EXAMPLE 3 When equimolar amounts of C H (CH )SiClH and tetradecene-l are reacted at about C. in the presence of chloroplatinic acid a higher alkyl substituted silane of the formula C H (C H (CH )SiCl is obtained. This chlorosilane adduct can be hydrolyzed by the addition of water to yield a low viscosity fluid of the formula C14H29(C6H5) 3) 3) s) 14 29- EXAMPLE 4 The lubrication properties and gel times of the various disiloxanes were determined by the 4-ball method in which a /2 inch steel ball is rotated against three stationary /2 inch steel balls at a rate of 1200 r.p.m. at a temperature of 167 F. for 30 minutes under loads of 4, and 40 kilograms. At the end of this time, the length and width of the scar formed on each stationary ball is measured and the average of these six measurements is taken as the wear scar diameter. The smaller the wear scar, the better the lubricant.

The gel times, an indication of stability at high temperatures, were determined by placing 10 grams of the disiloxane contained in a 50 ml. beaker in an air circulating oven at 450 F. and recording the time necessary to eifect gellation of the fluid.

The disiloxanes tested were:

Results are as follows:

Disiloxane No.1 No.2 No.3 No.4

Viscosity (cs.at 210F.) 3.9 5.6 6.0 8.7 Wear-scar (mm.) at load I 40kg 1.52 1.23 1.51 1.08 Geltlme(hrs.) 24-40 48 52 These data demonstrate that the disiloxanes of the invention are good lubricants. When compared to a gel time 4 of 11 hours for (CH SiO[C H -,(CH )SiO] Si(CH the high temperature stability of the novel disiloxanes is apparent.

Reasonable modification and variation are within the scope of the invention which is directed to novel disiloxanes.

That which is claimed is:

1. An organosilicon composition of the formula RR CH SiOSi CH R'R in which each R is independently selected from the group consisting of alkyl radicals having from 14 to 30 inclusive carbon atoms; and each R is independently selected from the group consisting of methyl and phenyl radicals.

2. The composition of claim 1 in which each R is a methyl radical.

3. The composition of claim 1 in which R is a phenyl radical.

4. The compound of claim 1 in which each R is a methyl radical and R is selected from the group consisting of alkyl radicals having from 22-28 carbon atoms, and mixtures thereof.

References Cited UNITED STATES PATENTS 2,451,664 10/1948 Daudt 260448.2 R 2,469,888 5/1948 Patnode 260448.2 R 2,486,162 10/1949 Hyde 260-448.2 R X 2,489,139 11/1949 Hyde et a1 260448.2 R 2,521,673 9/1950 Britton et a1. 260-4482 R X 2,992,263 7/1961 Brown 260-4482 R TOBIAS E. LEVOW, Primary Examiner P. F. SHAVER, Assistant Examiner US. Cl. X.R. 

